Empty name and typeref Attributes Persist in XML for Single Output Decision Table

[BiancaBode]

Description

According to the DMN 1.3 specification, when a single output decision table is used, the name and typeref attributes should not be present in the XML representation of the DMN model. However, in dmn-js, when we remove the name and type reference from the decision table output column in the editor, the resulting XML still contains empty name and typeref attributes in the <output> element.

This leads to validation issues because Drools interprets these empty attributes as still being explicitly set, which is non-compliant with the DMN 1.3 specification.

Steps to Reproduce

1. Open dmn-js and create a decision table with a single output.
2. Remove the name and typeref from the output column.
3. Export the DMN XML and inspect the <output> element.
4. Observe that <output name="" typeref="" /> still appears in the XML.
5. Run against Drools validation – it fails because the attributes are still present.

Expected Behavior

• When the name and typeref fields are removed from the editor, they should not appear in the exported XML at all.

Actual Behavior

• Even after removing these fields in the editor, they remain in the XML as empty attributes (name="" typeref=""), causing validation errors in Drools.

Environment

• dmn-js version: v.17.0.3
• Browser: Edge
• OS: Windows

[barmac]

I cannot reproduce the part of the issue regarding a single name. If I remove the name from an output, it is not present in the XML.

Screen.Recording.2025-02-13.at.15.01.04.mov

There is of course a question whether the output should preserve its name when it becomes the only one in the decision table, but that could go against the editing flow when the user models one output after another. We could also consider cleanup at the export, but that may go against the no surprises principle. I'd rather use linting for such cases.

Regarding typeRef, it should be removed when it's erased but isn't.

[barmac]

So my assessment is that for dmn-js we need to fix empty typeref, but not for a single output, but rather all outputs.
On top of that, a dmn linter could report problems as we do in bpmn-js ecosystem.